Commit e4d001b5 authored by Marc Zyngier's avatar Marc Zyngier Committed by Thomas Gleixner
Browse files

genirq/msi: Add helper for creating MSI-parent irq domains 



Creating an irq domain that serves as an MSI parent requires
a substantial amount of esoteric boiler-plate code, some of
which is often provided twice (such as the bus token).

To make things a bit simpler for the unsuspecting MSI tinkerer,
provide a helper that does it for them, and serves as documentation
of what needs to be provided.

Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/20250513172819.2216709-3-maz@kernel.org
parent e51b2743

include/linux/msi.h

+4 −0
Original line number Diff line number Diff line
@@ -636,6 +636,10 @@ struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode, 
					 struct msi_domain_info *info,

					 struct irq_domain *parent);



struct irq_domain_info;

struct irq_domain *msi_create_parent_irq_domain(struct irq_domain_info *info,

						const struct msi_parent_ops *msi_parent_ops);



bool msi_create_device_irq_domain(struct device *dev, unsigned int domid,

				  const struct msi_domain_template *template,

				  unsigned int hwsize, void *domain_data,

kernel/irq/msi.c

+26 −0
Original line number Diff line number Diff line
@@ -911,6 +911,32 @@ struct irq_domain *msi_create_irq_domain(struct fwnode_handle *fwnode, 
	return __msi_create_irq_domain(fwnode, info, 0, parent);

}



/**

 * msi_create_parent_irq_domain - Create an MSI-parent interrupt domain

 * @info:		MSI irqdomain creation info

 * @msi_parent_ops:	MSI parent callbacks and configuration

 *

 * Return: pointer to the created &struct irq_domain or %NULL on failure

 */

struct irq_domain *msi_create_parent_irq_domain(struct irq_domain_info *info,

						const struct msi_parent_ops *msi_parent_ops)

{

	struct irq_domain *d;



	info->hwirq_max		= max(info->hwirq_max, info->size);

	info->size		= info->hwirq_max;

	info->domain_flags	|= IRQ_DOMAIN_FLAG_MSI_PARENT;

	info->bus_token		= msi_parent_ops->bus_select_token;



	d = irq_domain_instantiate(info);

	if (IS_ERR(d))

		return NULL;



	d->msi_parent_ops = msi_parent_ops;

	return d;

}

EXPORT_SYMBOL_GPL(msi_create_parent_irq_domain);



/**

 * msi_parent_init_dev_msi_info - Delegate initialization of device MSI info down

 *				  in the domain hierarchy